Lehman College course GEP 630 with Prof. Johnson (Geo-statistics). The 3 maps show rates mapped to the to the ZIP code level. The first one uses the raw rates but the second and the third use two different types of parametric smoothing called Empirical Bayes (EB), a global version and a local version. Note that although all the maps show rates classified into 5 classes (natural breaks) the values for each class are not the same when the maps are compared.
Icelandic police officers doing some accident cluster analysis in 1968. (original image).
I’ve been thinking a lot about GIS teaching methods lately and how powerful a simple image (or a map) can be. Here’s my very simple stab at explaining a digital elevation model (DEM) represented as a raster, how the elevation is stored in a single cell and how we might think of it in 3D. Only a draft and would presented with minimal text for clarification. Data from The National Land Survey of Iceland.
Experimenting with a couple of things in ArcGIS like batch processing scripts and model shadows for the hillshade tool (and the Tumblr gif size limit!). Higher latitudes experience dramatic change in sunlight over a course of one year. This hillshade animations show sunlight for 21 June (summer solstice) in 2013 for the town of Isafjordur in Iceland located just north of 66°N on the spit in a fjord near the middle of the map. For some, there is no sunset. Ragnar Thrastarson - Lehman College GISc Program. Data: www.lmi.is/en
Lehman College course GEP 605 with Prof. Maantay and Prof. Maroko. Created with ArcGIS in 2013. Scenario: You were asked by an environmental group to estimate the average annual concentration of fine particulate matter (PM2.5) in New York City. As a point of reference, the National Ambient Air Quality Standard (NAAQS) for average annual concentration PM2.5 is 15µg/m3. You will be using EPA air quality monitor data (n=15).
Working with DMSP-OLS night-time light data. The map shows urban areas in SW Iceland. The five circled towns appear to be the same size, but they are not. The discrepancy is created by illumination from lights used by greenhouses. The three clustered areas can actually be seen in this awesome aurora image by Örvar A. Þorgeirson. More info on Icelandic greenhouses here.
More NYC bicycle stuff. The good ol´ dot density map is useful for many things, but has some disadvantages for sure. Part of lab work at Lehman College (Environmental Health GIS) with Prof. Maroko. Created with ArcGIS. This would be impossible without the great work of the NYPD Crash Data Band-Aid Project.
It’s the season. Yet another project in the making. Bicycle collisions in New York City, looking at spatial distribution and exploring some statistics and correlations (including elevated railways). Part of lab work at Lehman College (Environmental Health GIS) with Prof. Maroko. Created with ArcGIS. This would be impossible without the great work of the NYPD Crash Data Band-Aid Project (@crahsmapper).
- QGIS, a GIS for free
So, here is a link to QGIS. It appears to be free.
It may be useful if you haven’t seen it yet, but it may...